Cam surprise, not a good one either

[My427stang]

Inspected my custom Bullet solid flat tappet cam before stabbing it today and what a kick in the junk.  No idea what happened, It's a few years old now but not many miles on it.  Planned to use it in the EFI 461, I have a similar hydraulic grind, but I tend to like solids.  Need to think about plan B

This is the rear-most lobe on the cam, no other issues anywhere else.  Lots of casting slag on this grind compared to a comp, maybe it had something funky going on with the core, or I somehow missed it the first time. 

Believe it or not, the small chunk scares me more than the big one, the lifter does not hit too hard on the big part, but over the top of the lobe you can see the path goes right over the missing small chunk.

That cam ran good, it's a shame, and Bullet stuff is priced OK but not cheap

[machoneman]

Yeah Ross that looks like a casting flaw on the edge and based upon the location and color, maybe you missed it as it doesn't look like stray material took out that chunk.

[Nightmist66]

Interesting.......What did the lifter look like?


Here's my new custom ground Bullet SFT after only a 50min. break-in. Did everything imagineable to prevent issues. Even used the "cam saver" lifters. Also had a chipped lobe. lots of slag on mine too. The adjacent lobe and lifter were none too happy......

[My427stang]

Wow, I'll post a pic of mine later, cam looks the same, but my lifters could not look prettier.  A perfectly polished and small burnish pad, even on that lobe.  My guess is that it was riding right over it, but who knows what will happen with a different block and slightly different geometry, I can't change mine.

I truly think mine would continue to run, but not willing to chance it.

I thought everyone was using the same cam cores, but my Comp on the shelf sure doesn't have all the slag and chunks missing

[My427stang]

BTW, my cam was a loosely 282S copy, 236 @ .050 and .580 lift, but 112 LSA on 106 ICL.  The 445 really liked it and I figured I'd use it in the truck again

I have a nice Comp hyd flat tappet here, 280/230 286/236 around .560 lift depending on the rockers I use.  It should be pretty darn close in performance, but I just hate to give up duration on a stroker, we'll see, got some time to think about it

[plovett]

That is a bummer, man.  Sorry to hear that.

I lost a Bullet SFT cam a few years back.  I don't remember if the cam was jacked up like that, though.  I used Crower EDM lifters on the cam, so since I had different manufacturer's parts I didn't try to get anything from them. 

Figure about $300-$350 for a new custom cam and lifters?  My opinion is that now you can use this as an opportunity to fine tune the cam spec's for this specific engine?

JMO,

paulie

[FElony]

Witness marks on the other lobe makes me wonder if it pulled off a rack (at Bullet?), caught something, and smacked the side of the right lobe.

[Heo]

I think the casting look verry rough between the lobes like
some Russian casting, maby it just the pics but

[Barry_R]

Most domestic camshaft cores come from CWC Textron, and will have "CWC" cast into the core somewhere.  The raw castings are flame hardened on rollers over gas jets and then sent to a couple places - Camshaft Machine Company (CMC) in Jackson, MI or Engine Power Components (EPC) in Gran Haven, MI - where they get the bearing journals finished, front and rear end surface features drilled and turned, distributor gears robbed, and lobes rough ground.

At this stage, the cams are referred to as "UGLs" - unground lobes - and will either be finish ground and packaged at CMC or EPC for a multitude of private label companies, or sold to the various cam grinders for use in making custom cams.  Each UGL part number has limits as to how far you can go in terms of grind profile and lobe placement on a given core before you run too deep into the hardness layer or run "off the map" of the core's physical area.  You cannot always "make anything you want to".  If the hardened layer is too shallow to support the load it might chip or wear prematurely, if you are trying to use all the possible real estate on a certain UGL you might leave an untouched spot if the cast is not 100% perfect and the flaw don't get caught....

[My427stang]

Interesting. 

This one is a baby though, although it was wide LSA that could cut one side of the lobes a little deeper. Although that lobe should be the exhaust opening side, which would be the deeper cut side for a wider LSA

It's 271@.028, Bullet called it a 282S copy, I'd buy that using Comp's .015 rating, although I never measured .015 events, its 236 @ .050 and .586 at the valve

It's just the one spot, but it doesn't look like external damage, so you are likely onto it.  Quite honestly, it could live forever, or in the new block it could die instantly LOL  Murphy's Law now that I see it though

I am going to think on this one a bit, the hyd cam I have is a nice match for the truck, although 6 degrees less .050 on the intake side and less lift, but the EFI tends to calm things down too, so I may have one ground.  Nice thing is the small volume heads are pretty fast are on a bigger bore, so it should do well no matter what I choose

Barry or anyone else, do you ever dress that slag on the side of each lobe?  It shouldn't do harm bit I was surprised of the amount of lobes that had so many hanging chunks

[fryedaddy]

i like investigating things like this and i agree with Felony.the scratches to the left of the chips line up.i think it scratched and then dropped to the next lobe and chipped.there is even a scratch on the other side of the chipped lobe.the lifter might have smoothed out the center.

[FElony]

i like investigating things like this and i agree with FElony.

Your check is in the mail.

the scratches to the left of the chips line up.i think it scratched and then dropped to the next lobe and chipped.there is even a scratch on the other side of the chipped lobe.the lifter might have smoothed out the center.

Well-honed intuition is a wonderful thing. Just ask doug. 

[My427stang]

I am just pi$$ed off that the cam I decided to use was the one that is unusable LOL

The question is, go with the hyd cam (280/286 230/236 .563/.575 112 LSA on 106) or go with a fresh custom solid flat tappet again?

I am a solid flat tappet guy, but the spare cam is hear and free and matches pretty well for truck use.  I'll ponder a bit, and pick last minute.  The current 390 blows the tires off the truck, so not like it matters that much!

[FElony]

I am just pi$$ed off that the cam I decided to use was the one that is unusable LOL

The question is, go with the hyd cam (280/286 230/236 .563/.575 112 LSA on 106) or go with a fresh custom solid flat tappet again?

I am a solid flat tappet guy, but the spare cam is hear and free and matches pretty well for truck use.  I'll ponder a bit, and pick last minute.  The current 390 blows the tires off the truck, so not like it matters that much!

Just use what you got and stop the brain hemorrhaging. You have accumulated a pile of congealing blood at the bottom of my browser window, and my cursor is afraid to go near it.

[My427stang]

I am just pi$$ed off that the cam I decided to use was the one that is unusable LOL

The question is, go with the hyd cam (280/286 230/236 .563/.575 112 LSA on 106) or go with a fresh custom solid flat tappet again?

I am a solid flat tappet guy, but the spare cam is hear and free and matches pretty well for truck use.  I'll ponder a bit, and pick last minute.  The current 390 blows the tires off the truck, so not like it matters that much!

Just use what you got and stop the brain hemorrhaging. You have accumulated a pile of congealing blood at the bottom of my browser window, and my cursor is afraid to go near it.

LOL, that's likely drool, not too much motivation on this one. It's hard to say I am using my nugget for more than a hat rack when I am building an engine for a truck that is already running well.